Non-invasive detection of an analyte using decoupled transmit and receive antennas

ABSTRACT

A method of non-invasive detection of an analyte includes generating a transmit signal having at least two different frequencies each of which is in a radio or microwave frequency range of the electromagnetic spectrum, and transmitting the transmit signal into a target containing at least one analyte of interest using at least one transmit antenna/element. At least one receive antenna/element that is decoupled from the at least one transmit antenna/element is used to detect a response resulting from transmitting the transmit signal by the at least one transmit antenna/element into the target containing the at least one analyte of interest. In one embodiment, the at least one transmit antenna/element can have a first geometry and the at least one receive antenna/element can have a second geometry that is geometrically different from the first geometry.

FIELD

This disclosure relates generally to apparatus, systems and methods ofnon-invasively detecting an analyte via spectroscopic techniques usingnon-optical frequencies such as in the radio or microwave frequencybands of the electromagnetic spectrum. More specifically, thisdisclosure relates to a non-invasive analyte sensor that includes atransmit antenna and a receive antenna where the transmit and receiveantennas are decoupled from one another.

BACKGROUND

There is interest in being able to detect and/or measure an analytewithin a target. One example is measuring glucose in biological tissue.In the example of measuring glucose in a patient, current analytemeasurement methods are invasive in that they perform the measurement ona bodily fluid such as blood for fingerstick or laboratory-based tests,or on fluid that is drawn from the patient often using an invasivetranscutaneous device. There are non-invasive methods that claim to beable to perform glucose measurements in biological tissues. However manyof the non-invasive methods generally suffer from: lack of specificityto the analyte of interest, such as glucose; interference fromtemperature fluctuations; interference from skin compounds (i.e. sweat)and pigments; and complexity of placement, i.e. the sensing deviceresides on multiple locations on the patient's body.

SUMMARY

This disclosure relates generally to apparatus, systems and methods ofnon-invasively detecting an analyte via spectroscopic techniques usingnon-optical frequencies such as in the radio or microwave frequencybands of the electromagnetic spectrum. A non-invasive analyte sensordescribed herein includes at least one transmit antenna (which may alsobe referred to as a transmit element) that functions to transmit agenerated transmit signal in a radio or microwave frequency range of theelectromagnetic spectrum into a target containing an analyte ofinterest, and at least one receive antenna (which may also be referredto as a receive element) that functions to detect a response resultingfrom transmission of the transmit signal by the transmit antenna intothe target.

The transmit and receive antennas are decoupled from one another whichhelps to improve the detection capability of the non-invasive analytesensor. The decoupling between the transmit and receive antennas can beachieved using any one or more techniques that causes as much of thesignal as possible that is transmitted by the transmit antenna to enterthe target and that minimizes or even eliminates the amount ofelectromagnetic energy that is directly received by the receive antennafrom the transmit antenna without traveling into the target. Thedecoupling can be achieved by one or more intentionally fabricatedconfigurations and/or arrangements between the transmit and receiveantennas that is sufficient to decouple the transmit and receiveantennas from one another. In one non-limiting embodiment, thedecoupling can be achieved by the transmit antenna and the receiveantenna having intentionally different geometries from one another.Intentionally different geometries refers to different geometricconfigurations of the transmit and receive antennas that areintentional, and is distinct from differences in geometry of transmitand receive antennas that may occur by accident or unintentionally, forexample due to manufacturing errors or tolerances.

Another technique to achieve decoupling of the transmit and receiveantennas is to use an appropriate spacing between each antenna,depending upon factors such as output power, size of the antennas,frequency, and the presence of any shielding, so as to force aproportion of the electromagnetic lines of force of the transmit signalinto the target so they reach the analyte, thereby minimizing oreliminating as much as possible direct receipt of electromagnetic energyby the receive antenna directly from the transmit antenna withouttraveling into the target. This technique helps to ensure that theresponse detected by the receive antenna is measuring the analyte and isnot just the transmitted signal flowing directly from the transmitantenna to the receive antenna. In one embodiment, the sensor can use afirst pair of transmit and receive antennas that have a first spacingtherebetween, and a second pair of transmit and receive antennas thathave a second spacing therebetween that differs from the first spacing.

The techniques described herein can be used to detect the presence ofthe analyte of interest, as well an amount of the analyte or aconcentration of the analyte within the target. The techniques describedherein can be used to detect a single analyte or more than one analyte.The target can be any target, for example human or non-human, animal ornon-animal, biological or non-biological, that contains the analyte(s)that one may wish to detect. For example, the target can include, but isnot limited to, human tissue, animal tissue, plant tissue, an inanimateobject, soil, a fluid, genetic material, or a microbe. The analyte(s)can be any analyte, for example human or non-human, animal ornon-animal, biological or non-biological, that one may wish to detect.For example, the analyte(s) can include, but is not limited to, one ormore of blood glucose, blood alcohol, white blood cells, or luteinizinghormone.

In one embodiment, a non-invasive analyte sensor system can include adecoupled antenna array having at least one transmit antenna and atleast one receive antenna that are decoupled from one another. The atleast one transmit antenna and the at least one receive antenna arepositioned and arranged relative to a target containing at least oneanalyte of interest so that the at least one transmit antenna cantransmit a transmit signal into the target, and so that the at least onereceive antenna can detect a response. A transmit circuit iselectrically connectable to the at least one transmit antenna. Thetransmit circuit is configured to generate a transmit signal to betransmitted by the at least one transmit antenna, where the transmitsignal is in a radio or microwave frequency range of the electromagneticspectrum. In addition, a receive circuit is electrically connectable tothe at least one receive antenna. The receive circuit is configured toreceive a response detected by the at least one receive antennaresulting from transmission of the transmit signal by the at least onetransmit antenna into the target containing the at least one analyte ofinterest.

In one embodiment, the decoupling can be achieved by an intentionaldifference in geometry between the at least one transmit antenna and theat least one receive antenna. In another embodiment, decoupling can beachieved by arranging the at least one transmit antenna and the at leastone receive antenna with an appropriate spacing therebetween that issufficient to decouple the at least one transmit antenna and the atleast one receive antenna.

In another embodiment described herein, a non-invasive analyte sensorsystem can include a sensor housing and a decoupled detector arrayattached to the sensor housing. The decoupled detector array can have atleast one transmit element and at least one receive element. The atleast one transmit element can have a first geometry and the at leastone receive element can have a second geometry that is geometricallydifferent from the first geometry. In addition to or separately from thedifferent geometries, an appropriate spacing can be provided between theat least one transmit element and the at least one receive element thatis sufficient to decouple the transmit and receive elements from oneanother. The at least one transmit element is positioned and arranged totransmit a transmit signal into a target containing at least one analyteof interest and the at least one receive element is positioned andarranged to be able to detect a response. In this embodiment, the atleast one transmit element consists of a strip of conductive materialhaving at least one lateral dimension thereof greater than a thicknessdimension thereof, and the strip of conductive material of the at leastone transmit element is disposed on a substrate. In addition, in thisembodiment, the at least one receive element consists of a strip ofconductive material having at least one lateral dimension thereofgreater than a thickness dimension thereof, and the strip of conductivematerial of the at least one receive element is disposed on a substratewhich can be the same substrate or a different substrate than the atleast one transmit element. A transmit circuit is attached to the sensorhousing and is electrically connectable to the at least one transmitelement, where the transmit circuit is configured to generate a transmitsignal to be transmitted by the at least one transmit element, with thetransmit signal being in a radio or microwave frequency range of theelectromagnetic spectrum. In addition, a receive circuit is attached tothe sensor housing, and is electrically connectable to the at least onereceive element. The receive circuit is configured to receive a responsedetected by the at least one receive element resulting from transmissionof the transmit signal by the at the least one transmit element into thetarget containing the at least one analyte of interest.

In still another embodiment described herein, a non-invasive analytesensor system can include a sensor housing and a detector array attachedto the sensor housing. The detector array can have at least one transmitelement and at least one receive element that are decoupled from oneanother. The at least one transmit element can have a first geometry andthe at least one receive element can have a second geometry that isgeometrically different from the first geometry. In addition to orseparately from the different geometries, an appropriate spacing can beprovided between the at least one transmit element and the at least onereceive element that is sufficient to decouple the transmit and receiveelements from one another. The at least one transmit element ispositioned and arranged to transmit a transmit signal into a targetcontaining at least one analyte of interest and the at least one receiveelement is positioned and arranged to be able to detect a response. Inthis embodiment, the at least one transmit element and the at least onereceive element can both consist of a strip of conductive materialdisposed on a substrate. A transmit circuit is disposed within thesensor housing and is electrically connected to the at least onetransmit element. The transmit circuit is configured to generate atransmit signal to be transmitted by the at least one transmit element,where the transmit signal has at least two frequencies, each of which isin a range of about 10 kHz to about 100 GHz, for example about 300 MHzto about 6000 MHz. A receive circuit is also disposed within the sensorhousing and is electrically connected to the at least one receiveelement. The receive circuit is configured to receive a responsedetected by the at least one receive element resulting from transmissionof the transmit signal by the at least one transmit element into thetarget containing the at least one analyte of interest. In addition, arechargeable battery is disposed within the sensor housing for providingelectrical power to the detector array, the transmit circuit and thereceive circuit.

DRAWINGS

References are made to the accompanying drawings that form a part ofthis disclosure, and which illustrate embodiments in which theapparatus, systems and methods described in this specification can bepracticed.

FIG. 1 is a schematic depiction of a non-invasive analyte sensor systemwith a non-invasive analyte sensor relative to a target according to anembodiment.

FIGS. 2A-C illustrate different example orientations of antenna arraysthat can be used in the sensor system described herein.

FIGS. 3A-3I illustrate different examples of transmit and receiveantennas with different geometries.

FIGS. 4A, 4B, 4C and 4D illustrate additional examples of differentshapes that the ends of the transmit and receive antennas can have.

FIG. 5 is a schematic depiction of a sensor device according to anembodiment.

FIG. 6 is a flowchart of a method for detecting an analyte according toan embodiment.

FIG. 7 is a flowchart of analysis of a response according to anembodiment.

FIG. 8 illustrates a tabletop device that incorporates the non-invasiveanalyte sensor system described herein.

FIG. 9 illustrates a system that incorporates the tabletop device ofFIG. 8.

FIG. 10 illustrates another embodiment of a tabletop device thatincorporates the non-invasive analyte sensor system described herein.

Like reference numbers represent like parts throughout.

DETAILED DESCRIPTION

The following is a detailed description of apparatus, systems andmethods of non-invasively detecting an analyte via spectroscopictechniques using non-optical frequencies such as in the radio ormicrowave frequency bands of the electromagnetic spectrum. Anon-invasive analyte sensor includes a transmit antenna (which may alsobe referred to as a transmit element) that functions to transmit agenerated transmit signal that is in a radio or microwave frequencyrange of the electromagnetic spectrum into a target containing ananalyte of interest, and a receive antenna (which may also be referredto as a receive element) that functions to detect a response resultingfrom transmission of the transmit signal by the transmit antenna intothe target. The transmit antenna and the receive antenna are decoupledfrom one another which improves the detection performance of the sensor.

The transmit antenna and the receive antenna can be located near thetarget and operated as further described herein to assist in detectingat least one analyte in the target. The transmit antenna transmits asignal, which has at least two frequencies in the radio or microwavefrequency range, toward and into the target. The signal with the atleast two frequencies can be formed by separate signal portions, eachhaving a discrete frequency, that are transmitted separately at separatetimes at each frequency. In another embodiment, the signal with the atleast two frequencies may be part of a complex signal that includes aplurality of frequencies including the at least two frequencies. Thecomplex signal can be generated by blending or multiplexing multiplesignals together followed by transmitting the complex signal whereby theplurality of frequencies are transmitted at the same time. One possibletechnique for generating the complex signal includes, but is not limitedto, using an inverse Fourier transformation technique. The receiveantenna detects a response resulting from transmission of the signal bythe transmit antenna into the target containing the at least one analyteof interest.

The transmit antenna and the receive antenna are decoupled (which mayalso be referred to as detuned or the like) from one another. Decouplingrefers to intentionally fabricating the configuration and/or arrangementof the transmit antenna and the receive antenna to minimize directcommunication between the transmit antenna and the receive antenna,preferably absent shielding. Shielding between the transmit antenna andthe receive antenna can be utilized. However, the transmit antenna andthe receive antenna are decoupled even without the presence ofshielding.

The signal(s) detected by the receive antenna can be analyzed to detectthe analyte based on the intensity of the received signal(s) andreductions in intensity at one or more frequencies where the analyteabsorbs the transmitted signal. An example of detecting an analyte usinga non-invasive spectroscopy sensor operating in the radio or microwavefrequency range of the electromagnetic spectrum is described in WO2019/217461, the entire contents of which are incorporated herein byreference. The signal(s) detected by the receive antenna can be complexsignals including a plurality of signal components, each signalcomponent being at a different frequency. In an embodiment, the detectedcomplex signals can be decomposed into the signal components at each ofthe different frequencies, for example through a Fourier transformation.In an embodiment, the complex signal detected by the receive antenna canbe analyzed as a whole (i.e. without demultiplexing the complex signal)to detect the analyte as long as the detected signal provides enoughinformation to make the analyte detection. In addition, the signal(s)detected by the receive antenna can be separate signal portions, eachhaving a discrete frequency.

In one embodiment, the sensor described herein can be used to detect thepresence of at least one analyte in a target. In another embodiment, thesensor described herein can detect an amount or a concentration of theat least one analyte in the target. The target can be any targetcontaining at least one analyte of interest that one may wish to detect.The target can be human or non-human, animal or non-animal, biologicalor non-biological. For example, the target can include, but is notlimited to, human tissue, animal tissue, plant tissue, an inanimateobject, soil, a fluid, genetic material, or a microbe. Non-limitingexamples of targets include, but are not limited to, a fluid, forexample blood, interstitial fluid, cerebral spinal fluid, lymph fluid orurine, human tissue, animal tissue, plant tissue, an inanimate object,soil, genetic material, or a microbe.

The analyte(s) can be any analyte that one may wish to detect. Theanalyte can be human or non-human, animal or non-animal, biological ornon-biological. For example, the analyte(s) can include, but is notlimited to, one or more of blood glucose, blood alcohol, white bloodcells, or luteinizing hormone. The analyte(s) can include, but is notlimited to, a chemical, a combination of chemicals, a virus, a bacteria,or the like. The analyte can be a chemical included in another medium,with non-limiting examples of such media including a fluid containingthe at least one analyte, for example blood, interstitial fluid,cerebral spinal fluid, lymph fluid or urine, human tissue, animaltissue, plant tissue, an inanimate object, soil, genetic material, or amicrobe. The analyte(s) may also be a non-human, non-biological particlesuch as a mineral or a contaminant.

The analyte(s) can include, for example, naturally occurring substances,artificial substances, metabolites, and/or reaction products. Asnon-limiting examples, the at least one analyte can include, but is notlimited to, insulin, acarboxyprothrombin; acylcarnitine; adeninephosphoribosyl transferase; adenosine deaminase; albumin;alpha-fetoprotein; amino acid profiles (arginine (Krebs cycle),histidine/urocanic acid, homocysteine, phenylalanine/tyrosine,tryptophan); andrenostenedione; antipyrine; arabinitol enantiomers;arginase; benzoylecgonine (cocaine); biotinidase; biopterin; c-reactiveprotein; carnitine; pro-BNP; BNP; troponin; carnosinase; CD4;ceruloplasmin; chenodeoxycholic acid; chloroquine; cholesterol;cholinesterase; conjugated 1-βhydroxy-cholic acid; cortisol; creatinekinase; creatine kinase MM isoenzyme; cyclosporin A; d-penicillamine;de-ethylchloroquine; dehydroepiandrosterone sulfate; DNA (acetylatorpolymorphism, alcohol dehydrogenase, alpha 1-antitrypsin, cysticfibrosis, Duchenne/Becker muscular dystrophy, analyte-6-phosphatedehydrogenase, hemoglobin A, hemoglobin S, hemoglobin C, hemoglobin D,hemoglobin E, hemoglobin F, D-Punjab, beta-thalassemia, hepatitis Bvirus, HCMV, HIV-1, HTLV-1, Leber hereditary optic neuropathy, MCAD,RNA, PKU, Plasmodium vivax, sexual differentiation, 21-deoxycortisol);desbutylhalofantrine; dihydropteridine reductase; diptheria/tetanusantitoxin; erythrocyte arginase; erythrocyte protoporphyrin; esterase D;fatty acids/acylglycines; free β-human chorionic gonadotropin; freeerythrocyte porphyrin; free thyroxine (FT4); free tri-iodothyronine(FT3); fumarylacetoacetase; galactose/gal-1-phosphate;galactose-1-phosphate uridyltransferase; gentamicin; analyte-6-phosphatedehydrogenase; glutathione; glutathione perioxidase; glycocholic acid;glycosylated hemoglobin; halofantrine; hemoglobin variants;hexosaminidase A; human erythrocyte carbonic anhydrase I;17-alpha-hydroxyprogesterone; hypoxanthine phosphoribosyl transferase;immunoreactive trypsin; lactate; lead; lipoproteins ((a), B/A-1, β);lysozyme; mefloquine; netilmicin; phenobarbitone; phenytoin;phytanic/pristanic acid; progesterone; prolactin; prolidase; purinenucleoside phosphorylase; quinine; reverse tri-iodothyronine (rT3);selenium; serum pancreatic lipase; sissomicin; somatomedin C; specificantibodies (adenovirus, anti-nuclear antibody, anti-zeta antibody,arbovirus, Aujeszky's disease virus, dengue virus, Dracunculusmedinensis, Echinococcus granulosus, Entamoeba histolytica, enterovirus,Giardia duodenalisa, Helicobacter pylori, hepatitis B virus, herpesvirus, HIV-1, IgE (atopic disease), influenza virus, Leishmaniadonovani, leptospira, measles/mumps/rubella, Mycobacterium leprae,Mycoplasma pneumoniae, Myoglobin, Onchocerca volvulus, parainfluenzavirus, Plasmodium falciparum, polio virus, Pseudomonas aeruginosa,respiratory syncytial virus, rickettsia (scrub typhus), Schistosomamansoni, Toxoplasma gondii, Trepenoma pallidium, Trypanosomacruzi/rangeli, vesicular stomatis virus, Wuchereria bancrofti, yellowfever virus); specific antigens (hepatitis B virus, HIV-1);succinylacetone; sulfadoxine; theophylline; thyrotropin (TSH); thyroxine(T4); thyroxine-binding globulin; trace elements; transferrin;UDP-galactose-4-epimerase; urea; uroporphyrinogen I synthase; vitamin A;white blood cells; and zinc protoporphyrin.

The analyte(s) can also include one or more chemicals introduced intothe target. The analyte(s) can include a marker such as a contrastagent, a radioisotope, or other chemical agent. The analyte(s) caninclude a fluorocarbon-based synthetic blood. The analyte(s) can includea drug or pharmaceutical composition, with non-limiting examplesincluding ethanol; cannabis (marijuana, tetrahydrocannabinol, hashish);inhalants (nitrous oxide, amyl nitrite, butyl nitrite,chlorohydrocarbons, hydrocarbons); cocaine (crack cocaine); stimulants(amphetamines, methamphetamines, Ritalin, Cylert, Preludin, Didrex,PreState, Voranil, Sandrex, Plegine); depressants (barbiturates,methaqualone, tranquilizers such as Valium, Librium, Miltown, Serax,Equanil, Tranxene); hallucinogens (phencyclidine, lysergic acid,mescaline, peyote, psilocybin); narcotics (heroin, codeine, morphine,opium, meperidine, Percocet, Percodan, Tussionex, Fentanyl, Darvon,Talwin, Lomotil); designer drugs (analogs of fentanyl, meperidine,amphetamines, methamphetamines, and phencyclidine, for example,Ecstasy); anabolic steroids; and nicotine. The analyte(s) can includeother drugs or pharmaceutical compositions. The analyte(s) can includeneurochemicals or other chemicals generated within the body, such as,for example, ascorbic acid, uric acid, dopamine, noradrenaline,3-methoxytyramine (3MT), 3,4-Dihydroxyphenylacetic acid (DOPAC),Homovanillic acid (HVA), 5-Hydroxytryptamine (5HT), and5-Hydroxyindoleacetic acid (FHIAA).

Referring now to FIG. 1, an embodiment of a non-invasive analyte sensorsystem with a non-invasive analyte sensor 5 is illustrated. The sensor 5is depicted relative to a target 7 that contains an analyte of interest9. In this example, the sensor 5 is depicted as including an antennaarray that includes a transmit antenna/element 11 (hereinafter “transmitantenna 11”) and a receive antenna/element 13 (hereinafter “receiveantenna 13”). The sensor 5 further includes a transmit circuit 15, areceive circuit 17, and a controller 19. As discussed further below, thesensor 5 can also include a power supply, such as a battery (not shownin FIG. 1).

The transmit antenna 11 is positioned, arranged and configured totransmit a signal 21 that is the radio frequency (RF) or microwave rangeof the electromagnetic spectrum into the target 7. The transmit antenna11 can be an electrode or any other suitable transmitter ofelectromagnetic signals in the radio frequency (RF) or microwave range.The transmit antenna 11 can have any arrangement and orientationrelative to the target 7 that is sufficient to allow the analyte sensingto take place. In one non-limiting embodiment, the transmit antenna 11can be arranged to face in a direction that is substantially toward thetarget 7.

The signal 21 transmitted by the transmit antenna 11 is generated by thetransmit circuit 15 which is electrically connectable to the transmitantenna 11. The transmit circuit 15 can have any configuration that issuitable to generate a transmit signal to be transmitted by the transmitantenna 11. Transmit circuits for generating transmit signals in the RFor microwave frequency range are well known in the art. In oneembodiment, the transmit circuit 15 can include, for example, aconnection to a power source, a frequency generator, and optionallyfilters, amplifiers or any other suitable elements for a circuitgenerating an RF or microwave frequency electromagnetic signal. In anembodiment, the signal generated by the transmit circuit 15 can have atleast two discrete frequencies (i.e. a plurality of discretefrequencies), each of which is in the range from about 10 kHz to about100 GHz. In another embodiment, each of the at least two discretefrequencies can be in a range from about 300 MHz to about 6000 MHz. Inan embodiment, the transmit circuit 15 can be configured to sweepthrough a range of frequencies that are within the range of about 10 kHzto about 100 GHz, or in another embodiment a range of about 300 MHz toabout 6000 MHz. In an embodiment, the transmit circuit 15 can beconfigured to produce a complex transmit signal, the complex signalincluding a plurality of signal components, each of the signalcomponents having a different frequency. The complex signal can begenerated by blending or multiplexing multiple signals together followedby transmitting the complex signal whereby the plurality of frequenciesare transmitted at the same time.

The receive antenna 13 is positioned, arranged, and configured to detectone or more electromagnetic response signals 23 that result from thetransmission of the transmit signal 21 by the transmit antenna 11 intothe target 7 and impinging on the analyte 9. The receive antenna 13 canbe an electrode or any other suitable receiver of electromagneticsignals in the radio frequency (RF) or microwave range. In anembodiment, the receive antenna 13 is configured to detectelectromagnetic signals having at least two frequencies, each of whichis in the range from about 10 kHz to about 100 GHz, or in anotherembodiment a range from about 300 MHz to about 6000 MHz. The receiveantenna 13 can have any arrangement and orientation relative to thetarget 7 that is sufficient to allow detection of the response signal(s)23 to allow the analyte sensing to take place. In one non-limitingembodiment, the receive antenna 13 can be arranged to face in adirection that is substantially toward the target 7.

The receive circuit 17 is electrically connectable to the receiveantenna 13 and conveys the received response from the receive antenna 13to the controller 19. The receive circuit 17 can have any configurationthat is suitable for interfacing with the receive antenna 13 to convertthe electromagnetic energy detected by the receive antenna 13 into oneor more signals reflective of the response signal(s) 23. Theconstruction of receive circuits are well known in the art. The receivecircuit 17 can be configured to condition the signal(s) prior toproviding the signal(s) to the controller 19, for example throughamplifying the signal(s), filtering the signal(s), or the like.Accordingly, the receive circuit 17 may include filters, amplifiers, orany other suitable components for conditioning the signal(s) provided tothe controller 19. In an embodiment, at least one of the receive circuit17 or the controller 19 can be configured to decompose or demultiplex acomplex signal, detected by the receive antenna 13, including aplurality of signal components each at different frequencies into eachof the constituent signal components. In an embodiment, decomposing thecomplex signal can include applying a Fourier transform to the detectedcomplex signal. However, decomposing or demultiplexing a receivedcomplex signal is optional. Instead, in an embodiment, the complexsignal detected by the receive antenna can be analyzed as a whole (i.e.without demultiplexing the complex signal) to detect the analyte as longas the detected signal provides enough information to make the analytedetection.

The controller 19 controls the operation of the sensor 5. The controller19, for example, can direct the transmit circuit 15 to generate atransmit signal to be transmitted by the transmit antenna 11. Thecontroller 19 further receives signals from the receive circuit 17. Thecontroller 19 can optionally process the signals from the receivecircuit 17 to detect the analyte(s) 9 in the target 7. In oneembodiment, the controller 19 may optionally be in communication with atleast one external device 25 such as a user device and/or a remoteserver 27, for example through one or more wireless connections such asBluetooth, wireless data connections such a 4G, 5G, LTE or the like, orWi-Fi. If provided, the external device 25 and/or remote server 27 mayprocess (or further process) the signals that the controller 19 receivesfrom the receive circuit 17, for example to detect the analyte(s) 9. Ifprovided, the external device 25 may be used to provide communicationbetween the sensor 5 and the remote server 27, for example using a wireddata connection or via a wireless data connection or Wi-Fi of theexternal device 25 to provide the connection to the remote server 27.

With continued reference to FIG. 1, the sensor 5 may include a sensorhousing 29 (shown in dashed lines) that defines an interior space 31.Components of the sensor 5 may be attached to and/or disposed within thehousing 29. For example, the transmit antenna 11 and the receive antenna13 are attached to the housing 29. In some embodiments, the antennas 11,13 may be entirely or partially within the interior space 31 of thehousing 29. In some embodiments, the antennas 11, 13 may be attached tothe housing 29 but at least partially or fully located outside theinterior space 31. In some embodiments, the transmit circuit 15, thereceive circuit 17 and the controller 19 are attached to the housing 29and disposed entirely within the sensor housing 29.

The receive antenna 13 is decoupled or detuned with respect to thetransmit antenna 11 such that electromagnetic coupling between thetransmit antenna 11 and the receive antenna 13 is reduced. Thedecoupling of the transmit antenna 11 and the receive antenna 13increases the portion of the signal(s) detected by the receive antenna13 that is the response signal(s) 23 from the target 7, and minimizesdirect receipt of the transmitted signal 21 by the receive antenna 13.The decoupling of the transmit antenna 11 and the receive antenna 13results in transmission from the transmit antenna 11 to the receiveantenna 13 having a reduced forward gain (S₂₁) and an increasedreflection at output (S₂₂) compared to antenna systems having coupledtransmit and receive antennas.

In an embodiment, coupling between the transmit antenna 11 and thereceive antenna 13 is 95% or less. In another embodiment, couplingbetween the transmit antenna 11 and the receive antenna 13 is 90% orless. In another embodiment, coupling between the transmit antenna 11and the receive antenna 13 is 85% or less. In another embodiment,coupling between the transmit antenna 11 and the receive antenna 13 is75% or less.

Any technique for reducing coupling between the transmit antenna 11 andthe receive antenna 13 can be used. For example, the decoupling betweenthe transmit antenna 11 and the receive antenna 13 can be achieved byone or more intentionally fabricated configurations and/or arrangementsbetween the transmit antenna 11 and the receive antenna 13 that issufficient to decouple the transmit antenna 11 and the receive antenna13 from one another.

For example, in one embodiment described further below, the decouplingof the transmit antenna 11 and the receive antenna 13 can be achieved byintentionally configuring the transmit antenna 11 and the receiveantenna 13 to have different geometries from one another. Intentionallydifferent geometries refers to different geometric configurations of thetransmit and receive antennas 11, 13 that are intentional. Intentionaldifferences in geometry are distinct from differences in geometry oftransmit and receive antennas that may occur by accident orunintentionally, for example due to manufacturing errors or tolerances.

Another technique to achieve decoupling of the transmit antenna 11 andthe receive antenna 13 is to provide appropriate spacing between eachantenna 11, 13 that is sufficient to decouple the antennas 11, 13 andforce a proportion of the electromagnetic lines of force of thetransmitted signal 21 into the target 7 thereby minimizing oreliminating as much as possible direct receipt of electromagnetic energyby the receive antenna 13 directly from the transmit antenna 11 withouttraveling into the target 7. The appropriate spacing between eachantenna 11, 13 can be determined based upon factors that include, butare not limited to, the output power of the signal from the transmitantenna 11, the size of the antennas 11, 13, the frequency orfrequencies of the transmitted signal, and the presence of any shieldingbetween the antennas. This technique helps to ensure that the responsedetected by the receive antenna 13 is measuring the analyte 9 and is notjust the transmitted signal 21 flowing directly from the transmitantenna 11 to the receive antenna 13. In some embodiments, theappropriate spacing between the antennas 11, 13 can be used togetherwith the intentional difference in geometries of the antennas 11, 13 toachieve decoupling.

In one embodiment, the transmit signal that is transmitted by thetransmit antenna 11 can have at least two different frequencies, forexample upwards of 7 to 12 different and discrete frequencies. Inanother embodiment, the transmit signal can be a series of discrete,separate signals with each separate signal having a single frequency ormultiple different frequencies.

In one embodiment, the transmit signal (or each of the transmit signals)can be transmitted over a transmit time that is less than, equal to, orgreater than about 300 ms. In another embodiment, the transmit time canbe than, equal to, or greater than about 200 ms. In still anotherembodiment, the transmit time can be less than, equal to, or greaterthan about 30 ms. The transmit time could also have a magnitude that ismeasured in seconds, for example 1 second, 5 seconds, 10 seconds, ormore. In an embodiment, the same transmit signal can be transmittedmultiple times, and then the transmit time can be averaged. In anotherembodiment, the transmit signal (or each of the transmit signals) can betransmitted with a duty cycle that is less than or equal to about 50%.

FIGS. 2A-2C illustrate examples of antenna arrays 33 that can be used inthe sensor system 5 and how the antenna arrays 33 can be oriented. Manyorientations of the antenna arrays 33 are possible, and any orientationcan be used as long as the sensor 5 can perform its primary function ofsensing the analyte 9.

In FIG. 2A, the antenna array 33 includes the transmit antenna 11 andthe receive antenna 13 disposed on a substrate 35 which may besubstantially planar. This example depicts the array 33 disposedsubstantially in an X-Y plane. In this example, dimensions of theantennas 11, 13 in the X and Y-axis directions can be considered lateraldimensions, while a dimension of the antennas 11, 13 in the Z-axisdirection can be considered a thickness dimension. In this example, eachof the antennas 11, 13 has at least one lateral dimension (measured inthe X-axis direction and/or in the Y-axis direction) that is greaterthan the thickness dimension thereof (in the Z-axis direction). In otherwords, the transmit antenna 11 and the receive antenna 13 are eachrelatively flat or of relatively small thickness in the Z-axis directioncompared to at least one other lateral dimension measured in the X-axisdirection and/or in the Y-axis direction.

In use of the embodiment in FIG. 2A, the sensor and the array 33 may bepositioned relative to the target 7 such that the target 7 is below thearray 33 in the Z-axis direction or above the array 33 in the Z-axisdirection whereby one of the faces of the antennas 11, 13 face towardthe target 7. Alternatively, the target 7 can be positioned to the leftor right sides of the array 33 in the X-axis direction whereby one ofthe ends of each one of the antennas 11, 13 face toward the target 7.Alternatively, the target 7 can be positioned to the sides of the array33 in the Y-axis direction whereby one of the sides of each one of theantennas 11, 13 face toward the target 7.

The sensor 5 can also be provided with one or more additional antennaarrays in addition the antenna array 33. For example, FIG. 2A alsodepicts an optional second antenna array 33 a that includes the transmitantenna 11 and the receive antenna 13 disposed on a substrate 35 a whichmay be substantially planar. Like the array 33, the array 33 a may alsobe disposed substantially in the X-Y plane, with the arrays 33, 33 aspaced from one another in the X-axis direction.

In FIG. 2B, the antenna array 33 is depicted as being disposedsubstantially in the Y-Z plane. In this example, dimensions of theantennas 11, 13 in the Y and Z-axis directions can be considered lateraldimensions, while a dimension of the antennas 11, 13 in the X-axisdirection can be considered a thickness dimension. In this example, eachof the antennas 11, 13 has at least one lateral dimension (measured inthe Y-axis direction and/or in the Z-axis direction) that is greaterthan the thickness dimension thereof (in the X-axis direction). In otherwords, the transmit antenna 11 and the receive antenna 13 are eachrelatively flat or of relatively small thickness in the X-axis directioncompared to at least one other lateral dimension measured in the Y-axisdirection and/or in the Z-axis direction.

In use of the embodiment in FIG. 2B, the sensor and the array 33 may bepositioned relative to the target 7 such that the target 7 is below thearray 33 in the Z-axis direction or above the array 33 in the Z-axisdirection whereby one of the ends of each one of the antennas 11, 13face toward the target 7. Alternatively, the target 7 can be positionedin front of or behind the array 33 in the X-axis direction whereby oneof the faces of each one of the antennas 11, 13 face toward the target7. Alternatively, the target 7 can be positioned to one of the sides ofthe array 33 in the Y-axis direction whereby one of the sides of eachone of the antennas 11, 13 face toward the target 7.

In FIG. 2C, the antenna array 33 is depicted as being disposedsubstantially in the X-Z plane. In this example, dimensions of theantennas 11, 13 in the X and Z-axis directions can be considered lateraldimensions, while a dimension of the antennas 11, 13 in the Y-axisdirection can be considered a thickness dimension. In this example, eachof the antennas 11, 13 has at least one lateral dimension (measured inthe X-axis direction and/or in the Z-axis direction) that is greaterthan the thickness dimension thereof (in the Y-axis direction). In otherwords, the transmit antenna 11 and the receive antenna 13 are eachrelatively flat or of relatively small thickness in the Y-axis directioncompared to at least one other lateral dimension measured in the X-axisdirection and/or in the Z-axis direction.

In use of the embodiment in FIG. 2C, the sensor and the array 33 may bepositioned relative to the target 7 such that the target 7 is below thearray 33 in the Z-axis direction or above the array 33 in the Z-axisdirection whereby one of the ends of each one of the antennas 11, 13face toward the target 7. Alternatively, the target 7 can be positionedto the left or right sides of the array 33 in the X-axis directionwhereby one of the sides of each one of the antennas 11, 13 face towardthe target 7. Alternatively, the target 7 can be positioned in front ofor in back of the array 33 in the Y-axis direction whereby one of thefaces of each one of the antennas 11, 13 face toward the target 7.

The arrays 33, 33 a in FIGS. 2A-2C need not be oriented entirely withina plane such as the X-Y plane, the Y-Z plane or the X-Z plane. Instead,the arrays 33, 33 a can be disposed at angles to the X-Y plane, the Y-Zplane and the X-Z plane.

Decoupling Antennas Using Differences in Antenna Geometries

As mentioned above, one technique for decoupling the transmit antenna 11from the receive antenna 13 is to intentionally configure the transmitantenna 11 and the receive antenna 13 to have intentionally differentgeometries. Intentionally different geometries refers to differences ingeometric configurations of the transmit and receive antennas 11, 13that are intentional, and is distinct from differences in geometry ofthe transmit and receive antennas 11, 13 that may occur by accident orunintentionally, for example due to manufacturing errors or toleranceswhen fabricating the antennas 11, 13.

The different geometries of the antennas 11, 13 may manifest itself, andmay be described, in a number of different ways. For example, in a planview of each of the antennas 11, 13 (such as in FIGS. 3A-I), the shapesof the perimeter edges of the antennas 11, 13 may be different from oneanother. The different geometries may result in the antennas 11, 13having different surface areas in plan view. The different geometriesmay result in the antennas 11, 13 having different aspect ratios in planview (i.e. a ratio of their sizes in different dimensions; for example,as discussed in further detail below, the ratio of the length divided bythe width of the antenna 11 may be different than the ratio of thelength divided by the width for the antenna 13). In some embodiments,the different geometries may result in the antennas 11, 13 having anycombination of different perimeter edge shapes in plan view, differentsurface areas in plan view, and/or different aspect ratios. In someembodiments, the antennas 11, 13 may have one or more holes formedtherein (see FIG. 2B) within the perimeter edge boundary, or one or morenotches formed in the perimeter edge (see FIG. 2B).

So as used herein, a difference in geometry or a difference ingeometrical shape of the antennas 11, 13 refers to any intentionaldifference in the figure, length, width, size, shape, area closed by aboundary (i.e. the perimeter edge), etc. when the respective antenna 11,13 is viewed in a plan view.

The antennas 11, 13 can have any configuration and can be formed fromany suitable material that allows them to perform the functions of theantennas 11, 13 as described herein. In one embodiment, the antennas 11,13 can be formed by strips of material. A strip of material can includea configuration where the strip has at least one lateral dimensionthereof greater than a thickness dimension thereof when the antenna isviewed in a plan view (in other words, the strip is relatively flat orof relatively small thickness compared to at least one other lateraldimension, such as length or width when the antenna is viewed in a planview as in FIGS. 3A-I). A strip of material can include a wire. Theantennas 11, 13 can be formed from any suitable conductive material(s)including metals and conductive non-metallic materials. Examples ofmetals that can be used include, but are not limited to, copper or gold.Another example of a material that can be used is non-metallic materialsthat are doped with metallic material to make the non-metallic materialconductive.

In FIGS. 2A-2C, the antennas 11, 13 within each one of the arrays 33, 33a have different geometries from one another. In addition, FIGS. 3A-Iillustrate plan views of additional examples of the antennas 11, 13having different geometries from one another. The examples in FIGS.2A-2C and 3A-I are not exhaustive and many different configurations arepossible.

With reference initially to FIG. 3A, a plan view of an antenna arrayhaving two antennas with different geometries is illustrated. In thisexample (as well as for the examples in FIGS. 2A-2C and 3B-3I), for sakeof convenience in describing the concepts herein, one antenna is labeledas the transmit antenna 11 and the other antenna is labeled as thereceive antenna 13. However, the antenna labeled as the transmit antenna11 could be the receive antenna 13, while the antenna labeled as thereceive antenna 13 could be the transmit antenna 11. Each of theantennas 11, 13 are disposed on the substrate 35 having a planar surface37.

The antennas 11, 13 can be formed as linear strips or traces on thesurface 37. In this example, the antenna 11 is generally U-shaped andhas a first linear leg 40 a, a second linear leg 40 b that extendsperpendicular to the first leg 40 a, and a third linear leg 40 c thatextends parallel to the leg 40 a. Likewise, the antenna 13 is formed bya single leg that extends parallel to, and between, the legs 40 a, 40 c.

In the example depicted in FIG. 3A, each one of the antennas 11, 13 hasat least one lateral dimension that is greater than a thicknessdimension thereof (in FIG. 3A, the thickness dimension would extendinto/from the page when viewing FIG. 3A). For example, the leg 40 a ofthe antenna 11 extends in one direction (i.e. a lateral dimension) anextent that is greater than a thickness dimension of the leg 40 aextending into or out of the page; the leg 40 b of the antenna 11extends in a direction (i.e. a lateral dimension) an extent that isgreater than a thickness dimension of the leg 40 b extending into or outof the page; and the leg 40 c of the antenna 11 extends in one direction(i.e. a lateral dimension) an extent that is greater than a thicknessdimension of the leg 40 c extending into or out of the page. Likewise,the antenna 13 extends in one direction (i.e. a lateral dimension) anextent that is greater than a thickness dimension of the antenna 13extending into or out of the page.

The antennas 11, 13 also differ in geometry from one another in that thetotal linear length of the antenna 11 (determined by adding theindividual lengths L₁, L₂, L₃ of the legs 40 a-c together) when viewedin plan view is greater than the length L₁₃ of the antenna 13 whenviewed in plan view.

FIG. 3B illustrates another plan view of an antenna array having twoantennas with different geometries. In this example, the antennas 11, 13are illustrated as substantially linear strips each with a laterallength L₁₁, L₁₃, a lateral width W₁₁, W₁₃, and a perimeter edge E₁₁,E₁₃. The perimeter edges E₁₁, E₁₃ extend around the entire periphery ofthe antennas 11, 13 and bound an area in plan view. In this example, thelateral length L₁₁, L₁₃ and/or the lateral width W₁₁, W₁₃ is greaterthan a thickness dimension of the antennas 11, 13 extending into/fromthe page when viewing FIG. 3B. In this example, the antennas 11, 13differ in geometry from one another in that the shapes of the ends ofthe antennas 11, 13 differ from one another. For example, when viewingFIG. 3B, the right end 42 of the antenna 11 has a different shape thanthe right end 44 of the antenna 13. Similarly, the left end 46 of theantenna 11 may have a similar shape as the right end 42, but differsfrom the left end 48 of the antenna 13 which may have a similar shape asthe right end 44. It is also possible that the lateral lengths L₁₁, L₁₃and/or the lateral widths W₁₁, W₁₃ of the antennas 11, 13 could differfrom one another.

FIG. 3C illustrates another plan view of an antenna array having twoantennas with different geometries that is somewhat similar to FIG. 3B.In this example, the antennas 11, 13 are illustrated as substantiallylinear strips each with the lateral length L₁₁, L₁₃, the lateral widthW₁₁, W₁₃, and the perimeter edge E₁₁, E₁₃. The perimeter edges E₁₁, E₁₃extend around the entire periphery of the antennas 11, 13 and bound anarea in plan view. In this example, the lateral length L₁₁, L₁₃ and/orthe lateral width W₁₁, W₁₃ is greater than a thickness dimension of theantennas 11, 13 extending into/from the page when viewing FIG. 3C. Inthis example, the antennas 11, 13 differ in geometry from one another inthat the shapes of the ends of the antennas 11, 13 differ from oneanother. For example, when viewing FIG. 3C, the right end 42 of theantenna 11 has a different shape than the right end 44 of the antenna13. Similarly, the left end 46 of the antenna 11 may have a similarshape as the right end 42, but differs from the left end 48 of theantenna 13 which may have a similar shape as the right end 44. Inaddition, the lateral widths W₁₁, W₁₃ of the antennas 11, 13 differ fromone another. It is also possible that the lateral lengths L₁₁, L₁₃ ofthe antennas 11, 13 could differ from one another.

FIG. 3D illustrates another plan view of an antenna array having twoantennas with different geometries that is somewhat similar to FIGS. 3Band 3C. In this example, the antennas 11, 13 are illustrated assubstantially linear strips each with the lateral length L₁₁, L₁₃, thelateral width W₁₁, W₁₃, and the perimeter edge E₁₁, E₁₃. The perimeteredges E₁₁, E₁₃ extend around the entire periphery of the antennas 11, 13and bound an area in plan view. In this example, the lateral length L₁₁,L₁₃ and/or the lateral width W₁₁, W₁₃ is greater than a thicknessdimension of the antennas 11, 13 extending into/from the page whenviewing FIG. 3D. In this example, the antennas 11, 13 differ in geometryfrom one another in that the shapes of the ends of the antennas 11, 13differ from one another. For example, when viewing FIG. 3D, the rightend 42 of the antenna 11 has a different shape than the right end 44 ofthe antenna 13. Similarly, the left end 46 of the antenna 11 may have asimilar shape as the right end 42, but differs from the left end 48 ofthe antenna 13 which may have a similar shape as the right end 44. Inaddition, the lateral widths W₁₁, W₁₃ of the antennas 11, 13 differ fromone another. It is also possible that the lateral lengths L₁₁, L₁₃ ofthe antennas 11, 13 could differ from one another.

FIG. 3E illustrates another plan view of an antenna array having twoantennas with different geometries on a substrate. In this example, theantenna 11 is illustrated as being a strip of material having agenerally horseshoe shape, while the antenna 13 is illustrated as beinga strip of material that is generally linear. The planar shapes (i.e.geometries) of the antennas 11, 13 differ from one another. In addition,the total length of the antenna 11 (measured from one end to the other)when viewed in plan view is greater than the length of the antenna 13when viewed in plan.

FIG. 3F illustrates another plan view of an antenna array having twoantennas with different geometries on a substrate. In this example, theantenna 11 is illustrated as being a strip of material forming a rightangle, and the antenna 13 is also illustrated as being a strip ofmaterial that forms a larger right angle. The planar shapes (i.e.geometries) of the antennas 11, 13 differ from one another since thetotal area in plan view of the antenna 13 is greater than the total areain plan view of the antenna 11. In addition, the total length of theantenna 11 (measured from one end to the other) when viewed in plan viewis less than the length of the antenna 13 when viewed in plan.

FIG. 3G illustrates another plan view of an antenna array having twoantennas with different geometries on a substrate. In this example, theantenna 11 is illustrated as being a strip of material forming a square,and the antenna 13 is illustrated as being a strip of material thatforms a rectangle. The planar shapes (i.e. geometries) of the antennas11, 13 differ from one another. In addition, at least one of thewidth/length of the antenna 11 when viewed in plan view is less than oneof the width/length of the antenna 13 when viewed in plan.

FIG. 3H illustrates another plan view of an antenna array having twoantennas with different geometries on a substrate. In this example, theantenna 11 is illustrated as being a strip of material forming a circlewhen viewed in plan, and the antenna 13 is also illustrated as being astrip of material that forms a smaller circle when viewed in plansurrounded by the circle formed by the antenna 11. The planar shapes(i.e. geometries) of the antennas 11, 13 differ from one another due tothe different sizes of the circles.

FIG. 3I illustrates another plan view of an antenna array having twoantennas with different geometries on a substrate. In this example, theantenna 11 is illustrated as being a linear strip of material, and theantenna 13 is illustrated as being a strip of material that forms asemi-circle when viewed in plan. The planar shapes (i.e. geometries) ofthe antennas 11, 13 differ from one another due to the differentshapes/geometries of the antennas 11, 13.

4A-D are plan views of additional examples of different shapes that theends of the transmit and receive antennas 11, 13 can have to achievedifferences in geometry. Either one of, or both of, the ends of theantennas 11, 13 can have the shapes in FIGS. 4A-D, including in theembodiments in FIGS. 3A-I. FIG. 4A depicts the end as being generallyrectangular. FIG. 4B depicts the end as having one rounded corner whilethe other corner remains a right angle. FIG. 4C depicts the entire endas being rounded or outwardly convex. FIG. 4D depicts the end as beinginwardly concave. Many other shapes are possible.

Another technique to achieve decoupling of the antennas 11, 13 is to usean appropriate spacing between each antenna 11, 13 with the spacingbeing sufficient to force most or all of the signal(s) transmitted bythe transmit antenna 11 into the target, thereby minimizing the directreceipt of electromagnetic energy by the receive antenna 13 directlyfrom the transmit antenna 11. The appropriate spacing can be used byitself to achieve decoupling of the antennas 11, 13. In anotherembodiment, the appropriate spacing can be used together withdifferences in geometry of the antennas 11, 13 to achieve decoupling.

Referring to FIG. 2A, there is a spacing D between the transmit antenna11 and the receive antenna 13 at the location indicated. The spacing Dbetween the antennas 11, 13 may be constant over the entire length (forexample in the X-axis direction) of each antenna 11, 13, or the spacingD between the antennas 11, 13 could vary. Any spacing D can be used aslong as the spacing D is sufficient to result in most or all of thesignal(s) transmitted by the transmit antenna 11 reaching the target andminimizing the direct receipt of electromagnetic energy by the receiveantenna 13 directly from the transmit antenna 11, thereby decoupling theantennas 11, 13 from one another.

Referring to FIG. 5, an example configuration of the sensor device 5 isillustrated. In FIG. 5, elements that are identical or similar toelements in FIG. 1 are referenced using the same reference numerals. InFIG. 5, the antennas 11, 13 are disposed on one surface of a substrate50 which can be, for example, a printed circuit board. At least onebattery 52, such as a rechargeable battery, is provided above thesubstrate 50, for providing power to the sensor device 5. In addition, adigital printed circuit board 54 is provided on which the transmitcircuit 15, the receive circuit 17, and the controller 19 and otherelectronics of the second device 5 can be disposed. The substrate 50 andthe digital printed circuit board 54 are electrically connected via anysuitable electrical connection, such as a flexible connector 56. An RFshield 58 may optionally be positioned between the antennas 11, 13 andthe battery 52, or between the antennas 11, 13 and the digital printedcircuit board 54, to shield the circuitry and electrical components fromRF interference.

As depicted in FIG. 5, all of the elements of the sensor device 5,including the antennas 11, 13, the transmit circuit 15, the receivecircuit 17, the controller 19, the battery 52 and the like are containedentirely within the interior space 31 of the housing 29. In analternative embodiment, a portion of or the entirety of each antenna 11,13 can project below a bottom wall 60 of the housing 29. In anotherembodiment, the bottom of each antenna 11, 13 can be level with thebottom wall 60, or they can be slightly recessed from the bottom wall60.

The housing 29 of the sensor device 5 can have any configuration andsize that one finds suitable for employing in a non-invasive sensordevice. In one embodiment, the housing 29 can have a maximum lengthdimension L_(H) no greater than 50 mm, a maximum width dimension W_(H)no greater than 50 mm, and a maximum thickness dimension T_(H) nogreater than 25 mm, for a total interior volume of no greater than about62.5 cm³.

In addition, with continued reference to FIG. 5 together with FIGS.3A-3I, there is preferably a maximum spacing D_(max) and a minimumspacing D_(min) between the transmit antenna 11 and the receive antenna13. The maximum spacing D_(max) may be dictated by the maximum size ofthe housing 29. In one embodiment, the maximum spacing D_(max) can beabout 50 mm. In one embodiment, the minimum spacing D_(min) can be fromabout 1.0 mm to about 5.0 mm.

With reference now to FIG. 6 together with FIG. 1, one embodiment of amethod 70 for detecting at least one analyte in a target is depicted.The method in FIG. 6 can be practiced using any of the embodiments ofthe sensor device 5 described herein. In order to detect the analyte,the sensor device 5 is placed in relatively close proximity to thetarget. Relatively close proximity means that the sensor device 5 can beclose to but not in direct physical contact with the target, oralternatively the sensor device 5 can be placed in direct, intimatephysical contact with the target. The spacing between the sensor device5 and the target 7 can be dependent upon a number of factors, such asthe power of the transmitted signal. Assuming the sensor device 5 isproperly positioned relative to the target 7, at box 72 the transmitsignal is generated, for example by the transmit circuit 15. Thetransmit signal is then provided to the transmit antenna 11 which, atbox 74, transmits the transmit signal toward and into the target. At box76, a response resulting from the transmit signal contacting theanalyte(s) is then detected by the receive antenna 13. The receivecircuit 17 obtains the detected response from the receive antenna 13 andprovides the detected response to the controller 19. At box 78, thedetected response can then be analyzed to detect at least one analyte.The analysis can be performed by the controller 19 and/or by theexternal device 25 and/or by the remote server 27.

Referring to FIG. 7, the analysis at box 78 in the method 70 can take anumber of forms. In one embodiment, at box 80, the analysis can simplydetect the presence of the analyte, i.e. is the analyte present in thetarget. Alternatively, at box 82, the analysis can determine the amountof the analyte that is present.

FIG. 8 illustrates another example application of the non-invasiveanalyte sensor 5. In this example, the sensor 5 is incorporated into atabletop device 90. The term “tabletop” is used interchangeably with“countertop” and refers to a device that is intended to reside on a topsurface of a structure such as, but not limited to, a table, counter,shelf, another device, or the like during use. In some embodiments, thedevice 90 can be mounted on a vertical wall. The device 90 is configuredto obtain a real-time, on-demand reading of an analyte in a user suchas, but not limited to, obtaining a glucose level reading of the userusing the non-invasive analyte sensor 5 incorporated into the device 90.

The device 90 in FIG. 8 is illustrated as being generally rectangularbox shaped. However, the device 90 can have other shapes such ascylindrical, square box, triangular and many other shapes. The device 90includes a housing 92, a reading area 94, for example on a top surfaceof the housing 92, where the antennas 11, 13 of the sensor 5 arepositioned to be able to obtain a reading, and a display screen 96, forexample on the top surface of the housing 92, for displaying data suchas results of a reading by the sensor 5. Power for the device 90 can beprovided via a power cord 98 that plugs into a wall socket. The device90 may also include one or more batteries which act as a primary powersource for the device 90 instead of power provided via the power cord 98or the one or more batteries can act as a back-up power source in theevent power is not available via the power cord 98.

In operation of the device 90, a user places a body part adjacent to(i.e. in contact with or close to but not in contact with) the readingarea 94. The body part can be any digit of the user's hand, such as thethumb, the index finger, the middle finger, the ring finger or thelittle finger; or the user's wrist; or any other body part of the user.A reading by the device 90 is triggered by the user. The device 90 canbe configured in any manner with any form of a trigger mechanism topermit the user to trigger a reading. For example, the device 90 can beprovided with a trigger button 100 located anywhere thereon that whenpressed triggers a reading by the sensor 5. Alternatively, the device 90can include a proximity sensor, for example associated with the readingarea 94, that detects the presence of the user, such as the user's bodypart, adjacent to the reading area 94 and when detected initiates thereading. Alternatively, the device 90 can include a pressure sensor, forexample associated with the reading area 94, that detects contact of theuser's body part with the reading area 94 and when contact is detectedtriggers the reading by the sensor 5. Alternatively, the reading by thesensor 5 can be voice-triggered, for example by an optional microphone102 of the device 90 that picks up a predetermined reading-initiatingcommand that can be voiced by the user or a caregiver.

The results of a reading can be displayed on the display screen 96. Forexample, assuming the analyte being detected is glucose, the user'sglucose reading can be displayed on the display screen 96. In addition(or alternatively), the results of the reading can be audibly presentedby the device 90, for example via one or more speakers 104. The displayscreen 96 may be a touchscreen that permits user inputs, for example toscroll between different forms of display, or select differentfunctionality of the device 90. Alternatively, one or more input buttons(not shown) can be provided on the device 90 to allow user inputs.

An on/off power button or switch 106 can be provided anywhere on thedevice 90 to power the device 90 on and off. The on/off power button orswitch 106 could also function as the trigger button instead of thetrigger button 100. Alternatively, the trigger button 100 may act as anon/off power button to power the device 90 on and off, as well astrigger a reading. In one embodiment, the device 90 can be provided withsleep functionality whereby the device 90 enters a low power sleep modeafter a period of time of inactivity of the device 90. In the sleepmode, the trigger mechanism and/or the microphone 102 on the device 90can remain active waiting for suitable action to bring the device 90 outof the sleep mode and ready to take a reading. Examples of suitableactions include, but are not limited to, actuation of the triggermechanism or recognition of an audible voice command.

In some embodiments, the device 90 can include data storage for storingindividual readings for later historical analysis. Data for differentindividual users can also be stored in separate files for each user.

FIG. 10 illustrates another embodiment of the tabletop device 90 that issimilar to the device 90 in FIG. 8 and features that are similar tofeatures in FIG. 8 are referenced using the same reference numbers. InFIG. 10, instead of the display screen 96 being integrated into thedevice 90, the display screen 96 is part of a separate device that issuitably connected to the device 90 for example by a cable 108 such as aUSB cable. The separate display screen 96 in FIG. 10 may receive powerfrom the device 90, or the separate display screen 96 may have its ownpower source. In one embodiment, the display screen 96 can be atelevision screen of a television.

Referring to FIG. 9, a system that incorporates the tabletop device 90of either FIG. 8 or FIG. 10 is illustrated. In the illustrated system,the tabletop device 90 is in communication, either one-way or two-waycommunication, with one or more mobile devices 110 and/or with one ormore other remote devices 114. The mobile device(s) 110 can be, but isnot limited to, the user's mobile device; a parent's mobile device; anaide, nurse, doctor or other medical professional mobile device; or anyother mobile device. The mobile device(s) 110 can be a mobile phone, asmartwatch, a tablet device, a laptop computer, and the like. The remotedevice(s) 114 can be any device that is not a mobile device that is ableto interact and communicate with the device 90. For example, the device114 can be a base station that is designed to interact with the device90 and that may also interface with another remote device. The device 90and the mobile device(s) 110 and/or the remote device(s) 114 cancommunicate with one another via a suitable network 112, for example theinternet or other network. In other embodiments, the device 90 and themobile device(s) 110 and/or the remote device(s) 114 can directlycommunicate with each other, for example via a suitable short-rangewireless communication technique such as Bluetooth®.

In the system of FIG. 9, the results of a reading by the tabletop device90 can be transmitted, for example in real-time, to the mobile device(s)110 and/or the remote device(s) 114. For example, the results of thereading by the device 90 can be sent via phone call, email or by textmessage to the mobile device(s) 110 and/or the remote device(s) 114, ordirectly via wireless communication. The mobile device(s) 110 and/or theremote device(s) 114 can include an App that is configured to operatewith the device 90. In one non-limiting implementation, the system inFIG. 9 permits a reading, for example of an infant or a vulnerableadult, by the device 90 to be sent in real-time to a caregiver's (forexample, a parent, aide, nurse, doctor or other medical professional)mobile device 110. If the reading is abnormal, the caregiver can bealerted to that fact allowing the caregiver to render aid or arrange foraid to be rendered. In some embodiments, the signal received by themobile device(s) 110 and/or the remote device(s) 114 can cause themobile device(s) 110 and/or the remote device(s) 114 to emit an audibleand/or visual alert based on the reading transmitted from the device 90.The mobile device(s) 110 and/or the remote device(s) 114 may also sendone or more signals to the device 90. For example, a signal can be sentto the device 90 from the mobile device(s) 110 and/or the remotedevice(s) 114 after receiving a reading from the device 90 withinstructions to the user to take an action or with information relatingto the analyte sensed by the sensor. The instructions may be displayedon the display screen 96 of the device 90 and/or the device 90 mayaudibly present the instructions via the speaker 104.

The interaction between the transmitted signal and the analyte may, insome cases, increase the intensity of the signal(s) that is detected bythe receive antenna, and may, in other cases, decrease the intensity ofthe signal(s) that is detected by the receive antenna. For example, inone non-limiting embodiment, when analyzing the detected response,compounds in the target, including the analyte of interest that is beingdetected, can absorb some of the transmit signal, with the absorptionvarying based on the frequency of the transmit signal. The responsesignal detected by the receive antenna may include drops in intensity atfrequencies where compounds in the target, such as the analyte, absorbthe transmit signal. The frequencies of absorption are particular todifferent analytes. The response signal(s) detected by the receiveantenna can be analyzed at frequencies that are associated with theanalyte of interest to detect the analyte based on drops in the signalintensity corresponding to absorption by the analyte based on whethersuch drops in signal intensity are observed at frequencies thatcorrespond to the absorption by the analyte of interest. A similartechnique can be employed with respect to increases in the intensity ofthe signal(s) caused by the analyte.

Detection of the presence of the analyte can be achieved, for example,by identifying a change in the signal intensity detected by the receiveantenna at a known frequency associated with the analyte. The change maybe a decrease in the signal intensity or an increase in the signalintensity depending upon how the transmit signal interacts with theanalyte. The known frequency associated with the analyte can beestablished, for example, through testing of solutions known to containthe analyte. Determination of the amount of the analyte can be achieved,for example, by identifying a magnitude of the change in the signal atthe known frequency, for example using a function where the inputvariable is the magnitude of the change in signal and the outputvariable is an amount of the analyte. The determination of the amount ofthe analyte can further be used to determine a concentration, forexample based on a known mass or volume of the target. In an embodiment,presence of the analyte and determination of the amount of analyte mayboth be determined, for example by first identifying the change in thedetected signal to detect the presence of the analyte, and thenprocessing the detected signal(s) to identify the magnitude of thechange to determine the amount.

The terminology used in this specification is intended to describeparticular embodiments and is not intended to be limiting. The terms“a,” “an,” and “the” include the plural forms as well, unless clearlyindicated otherwise. The terms “comprises” and/or “comprising,” whenused in this specification, specify the presence of the stated features,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, and/or components.

The examples disclosed in this application are to be considered in allrespects as illustrative and not limitative. The scope of the inventionis indicated by the appended claims rather than by the foregoingdescription; and all changes which come within the meaning and range ofequivalency of the claims are intended to be embraced therein.

The invention claimed is:
 1. A method of non-invasive detection of ananalyte in interstitial fluid of a human body, comprising: using anon-invasive analyte sensor that is located outside the human body:generating a transmit signal using the non-invasive analyte sensor, thetransmit signal having at least two different frequencies each of whichis in a radio or microwave frequency range of the electromagneticspectrum; transmitting the transmit signal from the non-invasive analytesensor into the interstitial fluid of the human body using at least onetransmit antenna of the non-invasive analyte sensor; and using at leastone receive antenna of the non-invasive analyte sensor that is decoupledfrom the at least one transmit antenna to detect a response resultingfrom transmitting the transmit signal by the at least one transmitantenna into the interstitial fluid of the human body; analyzing theresponse to detect the analyte in the interstitial fluid.
 2. The methodof claim 1, wherein detecting the analyte comprises determining anamount of the analyte.
 3. The method of claim 1, wherein the analytecomprises glucose, alcohol, white blood cells, or luteinizing hormone.4. The method of claim 1, comprising: generating the transmit signal asa complex signal having the at least two different frequencies; or thetransmit signal has at least two separate signal portions, each signalportion having one of the at least two different frequencies.
 5. Themethod of claim 1, wherein the response includes a plurality offrequencies each associated with a respective one of the at least twodifferent frequencies.
 6. The method of claim 5, wherein theinterstitial fluid contains at least one additional analyte, and themethod further comprises analyzing the response to detect the at leastone additional analyte.
 7. The method of claim 6, wherein detecting theat least one additional analyte comprises determining an amount of theat least one additional analyte.
 8. The method of claim 6, wherein theat least one additional analyte comprises glucose, alcohol, white bloodcells, and luteinizing hormone.
 9. The method of claim 1, wherein eachof the at least two different frequencies falls within a range ofbetween about 10 kHz to about 100 GHz.
 10. A method of non-invasivelydetecting an analyte in interstitial fluid of a human body, comprising:using a non-invasive analyte sensor that is located outside the humanbody: generating a transmit signal using the non-invasive analytesensor, the transmit signal having at least two different frequencieseach of which falls within a range of between about 10 kHz to about 100GHz; transmitting the transmit signal from the non-invasive analytesensor into the interstitial fluid of the human body from at least onetransmit element of the non-invasive analyte sensor; and using at leastone receive element of the non-invasive analyte sensor that is decoupledfrom the at least one transmit element to detect a response resultingfrom transmitting the transmit signal by the at least one transmitelement into the interstitial fluid of the human body, and analyzing theresponse to detect the analyte in the interstitial fluid.
 11. The methodof claim 10, wherein detecting the analyte comprises determining anamount of the analyte.
 12. The method of claim 10, wherein the analytecomprises glucose, alcohol, white blood cells, or luteinizing hormone.13. The method of claim 10, comprising: generating the transmit signalas a complex signal having the at least two different frequencies; orthe transmit signal has at least two separate signal portions, eachsignal portion having one of the at least two different frequencies. 14.The method of claim 10, wherein the response includes a plurality offrequencies each associated with a respective one of the at least twodifferent frequencies.
 15. The method of claim 14, wherein theinterstitial fluid contains at least one additional analyte, and themethod further comprises analyzing the response to detect the at leastone additional analyte.
 16. The method of claim 15, wherein detectingthe at least one additional analyte comprises determining an amount ofthe at least one additional analyte.
 17. The method of claim 15, whereinthe at least one additional analyte comprises glucose, alcohol, whiteblood cells, and luteinizing hormone.
 18. The method of claim 1, whereina longitudinal axis of the at least one transmit antenna is parallel toa longitudinal axis of the at least one receive antenna, and thelongitudinal axis of the at least one transmit antenna does notintersect the at least one receive antenna.
 19. The method of claim 10,wherein a longitudinal axis of the at least one transmit element isparallel to a longitudinal axis of the at least one receive element, andthe longitudinal axis of the at least one transmit element does notintersect the at least one receive element.